SPECTRAL IDX TOOLKIT

An suite of spectral image processing and analysis tools for RSI and GIS professionals that plugs into ENVI.

Exogenesis has developed a fully automated suite of spectral image processing and analysis algorithms used in ENVI, by Harris Corp. Each one of the apps in our Spectral IDX Toolkit adds valuable time saving processing and analytical functionality to the skill set of you or your GIS and Imagery professional employees. From our atmospheric correction and spectral signature identification tools, to our automatic image-to-image co-registration and spectral library management tools, the Exogenesis Spectral IDX Toolkit will be a welcome addition to any GIS professional’s bag of geospatial tricks.

Click any of the expandable entries below to see each tool in detail and discover how it can bring value to your current and future geospatial operations.

This proprietary tool is used to automate the flat fielding atmospheric correction technique. The flat field calibration technique is used to normalize images to an area of known "flat" reflectance, and ordinarily requires a priori knowledge of the scene. This technique eliminates that requirement. Our iterative approach filters out highly skewed signatures through a series of radiance band filters and then calculates a first draft reflectance image. This reflectance image is more accurate than IARR or log residuals. Spectrally flat pixels are identified in the first reflectance image, and their radiance used to calculate a highly accurate second reflectance image.

ADVANTAGES:

More accurate than IARR yet no knowledge of the scene is required prior to correction.

No ground truth data is required to perform the correction.

LIMITATIONS:

Requires a hyperspectral scene with a region of interest that is spectrally uniform and flat and does not work in areas that are predominantly vegetation.

Material Identification - Spectral Signature Material Identifier

On-the-fly spectral resampling for ease and speed of use with any spectral library

Alchemy - Empirical Solar and Atmospheric Correction

DESCRIPTION:

Based upon the empirical finding that the average reflectance of diverse material spectra is not dependent on each scene, Alchemy is an in-scene approach to atmospheric correction and determines parameters directly from the information contained within the scene using the observed pixel spectra. Alchemy works by filtering out highly skewed signatures with a vegetation filter, and then calculates the average radiance of the remaining spectrally-pure endmembers. This method is user friendly and requires no a priori knowledge of the image while still producing reasonably accurate spectra. Alchemy enables the retrieval of reasonably accurate reflectance spectra even when the sensor does not have proper radiometric or wavelength calibration, or when the solar illumination intensity is unknown.

ADVANTAGES:

Does not require ground truth

LIMITATIONS:

Requires at least 10 endmembers and sufficiently dark pixels to allow for a baseline estimation

Can be skewed by scenes which are predominantly vegetation

Automated Image Co-Registration

DESCRIPTION:

Image co-registration is a process in which two or more images are geometrically aligned so that the analogous pixels of their shared features are integrated and correspond.